The present invention relates to a method for the hydrogenation treatment of a heavy hydrocarbon oil and, more particularly, to a method, in a two-step process for the hydrogenation treatment of a heavy hydrocarbon oil by use of a catalyst, by which the hydrogenation treatment can be effected and continued over a long period of time with high efficiency and stability by use of a specific catalyst in the first-step treatment.
Several processes are known in the prior art for the hydrogenation treatment of a heavy hydrocarbon oil including, for example, a method in which the heavy hydrocarbon oil is first demetallized followed by desulfurization, a method of successive desulfurization and hydrogenative cracking of the heavy hydrocarbon oil and a method using two kinds of catalysts having different relative activities for the desulfurization and demetallization reactions.
None of these prior art methods, however, is quite satisfactory in respect of the efficiency of the treatment and the stability of the reaction in long-term running of the process.